"angle shooting" is a preconceived concept that self-proclaimed "great" players from the maryland/kansas boards* brought to this (non-shitty board) in order to try to show off their self-proclaimed mafia superiority. Quite often it consists of an honest mistake like a civ forgetting that somebody died at "night" two rounds ago.
MD/KU posters like using this as a reason that they/their team lost in order to keep their veil of awesomeness (read: insecurity) in tact for future games.
It's stupid, completely subjective, and honestly, kind of pathetic.
*If you think I'm unfair here: name one non MD/KU poster or poster that plays/ed on those boards and considers himself a part of their club *cough*Knight*cough*GTB*cough* that has ever bitched about "angle shooting" on this board. Not a one will be found.